Product Overview

The Epro PR6424/011-101 16mm Eddy Current Sensor is a non-contact displacement sensor designed for monitoring the operating condition of critical rotating machinery. Part of the PR6424 sensor family associated with Emerson’s Epro machinery monitoring solutions, it is used to measure shaft displacement, vibration, position, and other mechanical parameters in industrial equipment.

Rotating machinery such as steam turbines, gas turbines, compressors, pumps, and generators operates under continuous mechanical and thermal stress. Changes in shaft vibration, radial displacement, axial position, or eccentricity can indicate developing mechanical problems. Accurate measurement of these conditions helps plant operators and maintenance teams evaluate equipment performance and identify abnormal operating trends.

The PR6424 series uses eddy current measurement technology. The sensor operates without physical contact with the rotating shaft, allowing it to measure small changes in the distance between the probe tip and a conductive target. This non-contact arrangement is particularly useful for machinery operating at high speeds or under demanding environmental conditions.

The PR6424 family features a nominal 16 mm sensor head and is designed for applications involving relatively large rotating shafts. Its documented measurement characteristics include a sensitivity of 4 V/mm, a static measurement range of ±2.0 mm, and a dynamic measurement range of 0 to 1,000 μm peak-to-peak.

The PR6424/011-101 is identified as a 16 mm eddy current sensor. Its specific cable length, connector arrangement, mounting thread, and other ordering details should be checked against the exact product label and configuration documentation before installation or replacement.

Technical Specifications

Note: The performance figures above describe the PR6424 sensor family. Confirm the precise suffix-specific cable, connector, temperature, and mounting specifications for PR6424/011-101 before ordering.

Function and Working Principle

1. Eddy Current Measurement Technology

The PR6424 sensor operates according to the eddy current principle. An alternating electrical signal in the sensor coil generates an electromagnetic field around the probe tip.

When a conductive metallic target approaches the sensor, the electromagnetic field induces eddy currents in the target material. These currents influence the electrical characteristics of the sensor coil.

The resulting change in the measurement circuit is related to the distance between the probe and the target. When used with a compatible signal converter, the sensor’s measurement response can be converted into an electrical output representing shaft displacement.

Because the measurement does not require physical contact, the sensor can monitor rotating shafts without introducing mechanical friction between the probe and the measured surface.

2. Shaft Displacement Measurement

Shaft displacement is an important parameter in rotating machinery monitoring. Excessive movement may be associated with bearing wear, shaft misalignment, mechanical looseness, or changing operating conditions.

The PR6424 sensor can measure the relative distance between its probe tip and the shaft surface. Changes in this distance provide information about shaft movement.

Depending on the installation, the sensor can be arranged to monitor radial or axial displacement. Correct probe positioning is essential to ensure that the measured movement corresponds to the intended mechanical parameter.

3. Vibration Monitoring

Dynamic shaft vibration is one of the important indicators used in rotating machinery condition monitoring.

When a shaft rotates, mechanical imbalance, misalignment, bearing problems, and other conditions can produce periodic movement. The PR6424 sensor detects changes in the shaft-to-probe gap and provides measurement information to the associated monitoring system.

The sensor family has a documented dynamic measurement range of 0 to 1,000 μm peak-to-peak. This capability supports vibration measurement in suitable large-shaft applications.

4. Position and Eccentricity Measurement

In addition to vibration, the sensor can be used for static position and eccentricity measurements.

Static position measurement provides information about the shaft’s relative location. Eccentricity measurement helps evaluate differences between the shaft’s geometric center and its rotational behavior.

These measurements can help maintenance teams investigate mechanical conditions and monitor changes during equipment operation.

5. Signal Conversion

The PR6424 sensor is normally used as part of a complete measurement chain rather than as a standalone monitoring instrument.

A compatible signal converter conditions the sensor response and provides an electrical signal for the monitoring or protection system. The converter must be matched to the sensor’s electrical characteristics and cable configuration.

The complete measurement chain may include:

• PR6424 eddy current sensor.
• Compatible extension cable, where required.
• Signal converter.
• Machinery monitoring or protection system.
• Control-room display and alarm equipment.

Compatibility between these components is essential for reliable measurement.

Role in Industrial Machinery Monitoring Systems

The PR6424/011-101 can form part of a machinery condition monitoring system. Its primary role is to provide non-contact measurements of shaft movement so that the monitoring system can evaluate the mechanical condition of rotating equipment.

Turbine Monitoring

Steam and gas turbines operate at high rotational speeds and require continuous monitoring of important mechanical parameters.

Eddy current sensors can be installed near selected shaft measurement locations to monitor relative displacement and vibration. The resulting information helps operators evaluate turbine operating conditions and identify abnormal mechanical behavior.

Compressor Monitoring

Industrial compressors are used in chemical processing, petrochemical facilities, gas transportation, and manufacturing plants.

Changes in shaft vibration or position can indicate mechanical problems that require further investigation. A properly configured PR6424 measurement system can supply shaft-related information to the compressor monitoring system.

Pump Monitoring

Large industrial pumps may operate continuously under varying process conditions. Shaft vibration and displacement measurements can help maintenance teams assess mechanical stability.

The PR6424 series is suitable for selected large-shaft applications where its measurement range and installation requirements match the pump design.

Generator Monitoring

Generators contain rotating assemblies that require reliable mechanical monitoring. Shaft displacement and vibration measurements can contribute to condition assessment and maintenance planning.

The sensor’s non-contact measurement method allows it to monitor shaft movement without direct mechanical contact.

Industrial Applications

1. Steam Turbines

Steam turbines are widely used in power generation and industrial energy systems. Their rotating shafts operate under substantial mechanical and thermal loads.

The PR6424 sensor can be incorporated into a suitable monitoring arrangement to measure shaft displacement and vibration. These measurements help operators assess changes in turbine mechanical behavior.

2. Gas Turbines

Gas turbines are used in power generation, industrial facilities, and mechanical drive applications. Reliable shaft monitoring is important because abnormal vibration or displacement can affect operating stability.

The sensor can provide non-contact shaft measurement when correctly matched to the monitoring system and installation requirements.

3. Centrifugal Compressors

Centrifugal compressors are common in petrochemical plants, refineries, and gas processing facilities.

The PR6424 sensor can monitor shaft movement in selected compressor configurations. Vibration and position information can be used together with other operating parameters to evaluate machinery condition.

4. Industrial Pumps

Large pumps are used in water treatment, power plants, chemical production, and oil and gas facilities.

Shaft displacement and vibration monitoring can help identify mechanical changes associated with bearings, alignment, or other rotating components.

5. Industrial Fans

Large fans and blowers are used in ventilation, cooling, combustion-air supply, and industrial process systems.

A suitable eddy current measurement system can monitor shaft movement and provide information for maintenance assessments.

6. Power Generation Equipment

In power generation facilities, rotating equipment reliability is closely related to plant availability and operating safety.

The PR6424 family can be used as part of a wider machinery protection arrangement where non-contact shaft measurements are required.

Installation and System Integration

Correct installation is essential for accurate measurement and reliable operation.

1. Verify the Sensor Configuration

Before installation, confirm the complete model number and inspect the sensor label.

The PR6424 family includes different cable, connector, mounting, and mechanical configurations. The suffix /011-101 should be checked against the corresponding ordering documentation to ensure that the replacement matches the existing installation.

2. Check the Mounting Arrangement

The sensor must be mounted securely at the specified measurement location.

The probe position should provide the required clearance from the shaft and allow the sensor to operate within its specified linear measurement range.

Avoid mounting arrangements that introduce unnecessary vibration or allow the probe to move during operation.

3. Set the Initial Air Gap

The distance between the probe tip and the target surface is an important installation parameter.

The PR6424 family has a nominal center air gap of approximately 2.7 mm. The actual installation setting must follow the applicable sensor and converter documentation.

Incorrect gap adjustment can reduce measurement accuracy or cause the measurement signal to operate outside the intended range.

4. Confirm Target Material

Eddy current sensor performance depends on the electrical and magnetic properties of the target material.

The PR6424 specifications identify ferromagnetic steel, with 42CrMo4 as the standard target material.

If the actual shaft material differs from the standard material, confirm the measurement system’s calibration requirements before commissioning.

5. Connect the Compatible Signal Converter

The sensor must be connected to a compatible signal converter using the specified cable and connector arrangement.

Check cable continuity, connector condition, shielding, and grounding according to the installation instructions.

Do not assume that every PR6424 sensor can be connected to every converter without checking the required electrical compatibility.

6. Inspect Cable Routing

The sensor cable should be routed away from sources of strong electromagnetic interference where practical.

Avoid excessive bending, crushing, abrasion, and contact with surfaces beyond the cable’s permitted temperature range.

Use appropriate cable protection in areas exposed to mechanical damage or harsh environmental conditions.

7. Perform Commissioning Checks

After installation, verify the initial air gap, converter configuration, measurement signal, and monitoring-system response.

Check the output under stationary conditions before evaluating dynamic measurements during equipment operation.

Record the installation position and commissioning values to support future maintenance and troubleshooting.

Compatible System Components

The PR6424/011-101 is normally integrated into a complete machinery monitoring chain.

The components listed above are examples of a typical monitoring arrangement. They are not necessarily included with the sensor.

Alternative Models and Replacement Considerations

The PR6424 belongs to a broader family of Epro eddy current sensors. Replacement selection should be based on measurement requirements and complete configuration compatibility.

Before selecting a replacement, verify:

• Complete sensor model and suffix.
• Probe diameter and mechanical dimensions.
• Mounting thread and installation length.
• Cable length and cable construction.
• Connector type and converter compatibility.
• Static and dynamic measurement ranges.
• Sensitivity and calibration requirements.
• Target material and shaft dimensions.
• Operating temperature and environmental conditions.
• Monitoring-system input and configuration.

A sensor with the same 16 mm diameter is not necessarily a direct replacement. Differences in cable and connector configuration can prevent correct integration even when the probe dimensions appear similar.

Key Advantages

Non-Contact Measurement

The eddy current principle allows the sensor to measure shaft movement without physical contact with the rotating target.

Shaft Displacement Monitoring

The sensor family supports static displacement measurement, helping monitoring systems evaluate shaft position and movement.

Dynamic Vibration Measurement

Its dynamic measurement capability makes it suitable for selected rotating machinery vibration monitoring applications.

Compact 16 mm Probe Design

The 16 mm sensor head provides a practical form factor for installation in suitable machinery measurement locations.

Industrial Machinery Applications

The PR6424 family is designed for critical rotating equipment such as turbines, compressors, pumps, and fans.

Stable Measurement Characteristics

The documented sensitivity, linearity, and long-term drift specifications support accurate measurement when the sensor is correctly installed and calibrated.

Integration with Machinery Monitoring Systems

When paired with a compatible signal converter, the sensor can supply measurement information to industrial monitoring and protection equipment.

Technical FAQs

1. What is the Epro PR6424/011-101?

It is a 16 mm eddy current sensor designed for non-contact measurement of shaft displacement and vibration in rotating machinery.

2. What is the sensor head diameter?

The nominal sensor head diameter is 16 mm.

3. What is the measurement principle?

It uses the eddy current principle. An electromagnetic field interacts with the conductive target, and changes in the sensor response are used to determine the distance between the probe and the target.

4. What is the static measurement range of the PR6424 family?

The documented static measurement range is ±2.0 mm.

5. What is its dynamic measurement range?

The documented dynamic measurement range is 0 to 1,000 μm peak-to-peak.

6. What is the sensitivity?

The PR6424 family has a specified sensitivity of 4 V/mm, with a maximum linearity deviation of ±1.5% under the specified measurement conditions.

7. What equipment can use this sensor?

Typical applications include steam turbines, gas turbines, hydro turbines, compressors, pumps, fans, and other large rotating machinery.

8. Does the sensor work independently?

It is normally used with a compatible signal converter and associated monitoring equipment. The converter processes the sensor response and supplies a usable measurement signal.

9. What is the sensor’s weight?

The supplied product weight is approximately 0.2 kg. The PR6424 family specification also gives approximately 200 grams for the sensor with a 1-meter cable and without armor.

10. Can it replace another 16 mm eddy current sensor?

Not automatically. Confirm the full model number, cable arrangement, connector, mounting dimensions, calibration, converter compatibility, and measurement requirements before substitution.

Procurement and Maintenance Recommendations

When purchasing the Epro PR6424/011-101, verify the complete model number and the physical configuration of the supplied sensor. The 16 mm probe diameter and approximate 0.2 kg weight are useful identification details, but they do not establish full electrical or mechanical compatibility.

For replacement projects, compare the existing sensor’s cable length, connector, mounting thread, insertion length, and signal converter requirements. If the sensor is part of a machinery protection system, confirm that the replacement can maintain the required measurement characteristics and calibration.

During maintenance, inspect the probe tip, cable insulation, connectors, mounting hardware, and surrounding installation area. Look for mechanical damage, loose mounting, contamination, or cable deterioration.

Where measurement values become unstable, check the complete measurement chain rather than replacing the sensor immediately. Possible causes include incorrect air-gap adjustment, cable damage, connector problems, target-surface conditions, converter faults, or incorrect system configuration.

Keep a record of the sensor model, installation location, air-gap setting, converter configuration, and commissioning measurements. This information can simplify future replacement and troubleshooting.

Conclusion

The Epro PR6424/011-101 16mm Eddy Current Sensor is designed for non-contact shaft displacement and vibration measurement in industrial rotating machinery. Its PR6424 family specifications include 4 V/mm sensitivity, a ±2.0 mm static measurement range, and a dynamic range of 0 to 1,000 μm peak-to-peak.

With a 16 mm sensor head and an approximate product weight of 0.2 kg, it is suitable for integration into compatible machinery monitoring arrangements used with turbines, compressors, pumps, and fans.

For reliable operation, engineers should verify the complete sensor configuration, mounting arrangement, cable and connector details, signal converter compatibility, and calibration requirements before installation or replacement.